1. Field of the Invention
The present invention relates to a retainer for fastening a component, especially a fuel distributor, to an internal combustion engine, as well as a system that preferably is a fuel-injection system or a part of a fuel-injection system. The invention relates especially to the domain of fuel-injection systems of internal combustion engines, where fuel under high pressure is injected into assigned combustion chambers of the internal combustion engine via fuel injectors.
2. Description of the Related Art
The published German Patent Application document DE 10 2010 046 344 A1 describes an engine assembly having a fuel rail. The engine assembly includes a cylinder head, a cam cover and a fuel-rail assembly. The fuel-rail assembly has the fuel rail, a clamp assembly and a fuel-injection device. The fuel rail of the engine assembly is attached to the cam cover. Meanwhile, the clamp assembly is secured to the fuel rail, it including a fastening element and an insulation element. The fastening element engages with the cam cover and secures the fuel rail to it. In one possible development, the fastening assembly may have fastening elements, spacers and a sleeve as well as a first and a second insulation element. The fastening elements have a head and a shank having a threaded area that engages with an opening in the cam cover in order to secure the fuel rail to the cam cover. The fastening element extends through the sleeve. The first insulation element is situated axially between a first side of the clamp and the cam cover. The second insulation element is situated axially between the second side of the clamp and the head of the fastening element. The insulation elements may be formed of an elastomer material that provides damping.
The engine assembly described in the published German Patent Application document DE 10 2010 046 344 A1 has the disadvantage that the insulation elements made of the elastomer material are secured by the head of the fastening element, which is screwed into the cam cover, via the spacer. Thus, both the attachment to the cam cover and the fixation of the insulation elements are effected by the fastening element. Since the tightening torque of the fastening element must be great, two possible cases are therefore possible with regard to dimensioning of the spacer. If the spacer is somewhat too short, a play of the clamp then results between the insulation elements, which impairs functioning considerably, so that this case must be avoided. If, taking possible tolerances into consideration, the spacer is made somewhat too long, then high compression of the insulation elements results locally, which cannot be avoided because of the high tightening torque required. This high compression then leads to a local component fatigue at the insulation elements, namely, in the area of the spacer on one hand, and on the other hand, at a graduated area of a sleeve against which the first insulation element is supported. A certain variance subject to tolerance results in this connection. External areas no longer contribute here to the fixation of the clamp relative to the insulation elements, since the support partners are lacking here, that is, the preloading disappears. This also has an unfavorable effect on the possible vibration damping. A variance occurs subject to tolerance in this case, as well.